Significance and Use
The alanine-EPR dosimetry system provides a means for measuring absorbed dose. It is based on the measurement of specific stable free radicals in crystalline alanine generated by ionizing radiation.
Alanine-EPR dosimetry systems are used in reference- or transfer-standard or routine dosimetry systems in radiation applications that include: sterilization of medical devices and pharmaceuticals, food irradiation, polymer modifications, medical therapy and radiation damage studies in materials (1, 13-15).
Scope
1.1 This practice covers dosimeter materials, instrumentation, and procedures for using the alanine-EPR dosimetry system for measuring the absorbed dose in the photon and electron radiation processing of materials. The system is based on electron paramagnetic resonance (EPR) spectroscopy of free radicals derived from the amino acid alanine.
1.2 The alanine dosimeter is classified as a type I dosimeter as it is affected by individual influence quantities in a well-defined way that can be expressed in terms of independent correction factors (see ASTM Practice E2628). The alanine dosimeter may be used in either a reference standard dosimetry system or in a routine dosimetry system.
1.3 This document is one of a set of standards that provides recommendations for properly implementing dosimetry in radiation processing, and describes a means of achieving compliance with the requirements of ASTM E2628 “Practice for Dosimetry in Radiation Processing” for alanine dosimetry system. It should be read in conjunction with ASTM E2628.
1.4 This practice covers alanine-EPR dosimetry systems for dose measurements under the following conditions:
1.4.1 The absorbed dose range is between 1 and 1.5 × 105Gy.
1.4.2 The absorbed dose rate is up to 102Gy s-1 for continuous radiation fields and up to 3 × 1010Gy s-1 for pulsed radiation fields (1-4).
1.4.3 The radiation energy for photons and electrons is between 0.1 and 30 MeV (1, 2, 5-8).
1.4.4 The irradiation temperature is between –78 °C and + 70 °C (2, 9-12).
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.